1. Field of the Invention
The present invention relates to a desk-top cutting machine whose saw can be tilted rightward and leftward relative to the top of the base of the machine.
2. Description of the Prior Art
FIGS. 6 and 7 show a conventional desk-top cutting machine in which a saw shaft 9 supporting a saw 10, and the shaft 12 of a motor 11 are connected to each other through toothed engagement to transmit the motive power of the motor to the saw. Since the saw shaft 9 and the motor shaft 12 are disposed in parallel with each other, the motor 11 projects sideward from a circular saw assembly 8.
To tilt the circular saw assembly 8, a clamping lever 5 is loosened, a holder 6 is tilted, and the lever is thereafter tightened to keep the holder at a desired tilt angle. When a workpiece is normally cut by the tilted saw assembly 8, the angle of the desired tilt is usually 45 degrees. However, the end 15a of a motor housing 15 comes into contact with the top of base 1 when the saw assembly 8 is tilted rightward by an angle of 20 to 30 degrees, as shown in FIG. 7. For that reason, the workpiece cannot be cut at 45 degrees. Therefore, to cut the workpiece, the saw assembly 8 is tilted leftward, the workpiece is cut at the left-hand end and then the workpiece is flipped around and cut at the right-hand end. This means that the efficiency of the cutting work is very low.
To solve this problem, a tiltable circular saw assembly was developed as disclosed in Japanese Utility Model Application (OPI) No. 49901/88. In this machine, a saw shaft and a motor shaft are connected to each other through a bevel gear and a bevel pinion, and the motor housing extends transverse to the saw shaft, so that even if the circular saw assembly is tilted toward the side of the motor by an angle of 45 degrees, a space is left between the top of the base and the end of the housing to make it possible to cut the workpiece with the saw assembly tilted rightward. However, the bevel gear and the bevel pinion are expensive means for motive power transmission. Also, a gear box of high accuracy needs to be provided to reduce backlash between the gear and the pinion, the axes of which orthogonally intersect each other.
To cut the workpiece using the latter machine, the workpiece is supported on the top of the base, a clamping lever is loosened, a holder is swung rightward or leftward to tilt the saw assembly into a desired position, the lever is thereafter tightened to keep the saw assembly in position, and the assembly is then swung down to cut into the workpiece. After cutting the workpiece, the circular saw assembly is moved back to the uppermost location thereof. To cut the workpiece without a tilt, the zero-tilt graduation of a tilt scale provided on the holder is set using an indicator provided on a turntable, to put the holder in position, the clamping lever is then tightened to keep the holder in position, and the saw assembly is thereafter moved down to cut into the workpiece. However, since a tilt scale and the indicator are used to set the circular saw assembly at a zero-tilt angle, the assembly is likely to be inaccurately set at the zero angle due to parallax. Since the heavy circular saw assembly is swung rightward or leftward to be set at a desired tilt angle, it is difficult to accurately perform angular setting.